Remove hovering effect from image in navigation bar

In my navigation bar, I’m adding social media icons to the right, for which I do not want to have any hovering effects. Notice the twitter icon in the right, and how there is a hovering effect over it. I wish to remove that and also wish for the navigation bar to not increase in size because of this icon. You’ll notice the vertical change in height after logging in, as for now I’m only displaying the icon after being logged in (until after I have this fixed).